The coffee jug holds 4 times as much as the milk jug. everyone has the same size cup, but each person likes different amounts of milk in their coffee. jane likes half milk and half coffee; jean, june and joan each like one quarter milk; and ian drinks black coffee. they fill up their five cups the way they each like and just empty one of the jugs. how much liquid is left in the other?

4x+y=t
3/4z+3/4z+3/4z+1/2z=Milk Jug Quantity= 2.75 Cups
1/4c+1/4c+1/4c+1/2c+1=Total coffee drunk=2.25 Cups

Since more milk has been drunk, and one of the jugs in empty, considering the fact that the coffee jug has 4 more times more liquid, it is implied that the milk jug is complete. And we know the amount of milk in the jug is 2.25, multiplying this by 4, we get 9, 9 cups. That is the total quantity of coffee. Subracting 2.25 from 9 is equal to 6.75 cups which is the amount of coffee left in the coffee jug.